1. Field of the Invention
The present invention relates to antigenic preparations comprising polysaccharides and/or glycopeptides preparable from keratinophilic fungi as well as yeasts, processes for the preparation of these antigenic preparations, their use as pharmaceutical substances as well as their use as vaccines, including but not limited to, the prophylaxis and treatment of allergy, as well as for modulating the immune response.
2. Description of Related Art
Allergy in one form or another afflicts more than 20 per cent of the human population, and the alarming increase in its prevalence, morbidity and mortality over the past decade has led to its designation as the number one environmental disease (Sutton and Gould, Nature 1993, 366, pp. 421–428). Human and animal populations are afflicted by allergy to a similar extent.
In the development of allergy, immunological reactions play a key role (Paul, William E.(Editor), Fundamental Immunology, Raven Press Books, Ltd., New York, 1984). In principle two different types of allergic reactions have been described. One is immediate type hypersensitivity (ITH), for which the maximum allergic response to the allergen is observed within minutes to hours. The second is delayed type hypersensitivity (DTH). In case of DTH, the allergic response to the allergen usually reaches its maximum after 24 to 48 hours. Most likely ITH is mediated predominantly via the IgE pathway, whereas DTH is more complex. In the development of DTH it is likely that further cell mediated responses (i.e. B- and T-lymphocytes) are involved. For example, after transferring lymphocytes and antibodies from allergic donor animals to non-allergic recipient animals, the recipients developed DTH (Askenase, P. W. (1973), J. exp. Med., 138, pp. 1144–1155).
Because of their direct exposure to environmental antigens, tissues most afflicted by allergies are the epithelial tissues, especially the skin. For example, in the dermatological clinic, acute allergic contact dermatitis and chronic allergic contact eczema account for up to 15% of all dermatoses. Allergic asthma accounts for about 20% of all asthma cases in humans.
Allergic diseases that can be classified as ITH, are for example atopic eczema, allergic bronchial asthma, hay fever, rhinitis, conjunctivitis. These can develop into chronic forms as well and should not be considered exclusively as IgE-dependent reactions. Examples of DTH are acute allergic contact dermatitis and chronic allergic contact eczema, which can further be classified as DTH (type IV) with epidermal involvement. Such a patient would have previously been sensitised through contact with an allergen and has developed hypersensitivity. Renewed contact with the allergen results in acute, sub-acute or chronic inflammatory contact dermatitis.
One example for an allergic dermatitis from the veterinary clinic is Summer Eczema, also called Sweet or Queens land Itch. Summer Eczema is an allergic dermatitis of horses, belonging to the atopic form of allergic diseases (involving Type I and IV reactions). Summer Eczema is provoked by the bite of midges of the families Culicidae and Ceratopgonidae, and characterised by skin lesions with permanent erosions and exudations, mainly in regions of the mane, tail, and abdomen. Afflicted animals display a strong sensitivity of the skin with regard to irritations, i.e. touch, rain, wind etc., impairing their overall health and performance. As with other allergies, it is believed that the development of this disease is also influenced by nutritional factors. The symptoms of this disease are only visible from March to September, whereas the allergen induced sensitivity of the skin is observed during the whole year. Summer Eczema provides an interesting-general model system for the study of allergy and for the development of anti-allergic substances.
Many treatments for allergy have been proposed, depending on the clinical picture. For the treatment of acute allergic contact dermatitis, chronic allergic contact eczema and/or atopic eczema usually lipophilic creams comprising glucocorticosteroids, anti-microbial substances, anti-inflammatory drugs and/or calcium are used. For the treatment of Summer Eczema various compounds have been applied locally or parenterally, for example steroid preparations, insecticides, different galenic formulations, salicylates, oils or peptides isolated from micro-organisms. All of the above treatments only deal with the symptoms and not the causes of allergy.
Impaired immune response or immunodeficiency often play important roles in the development of allergy. Therefore, also immunotherapeutic methods, for example the administration of immune-stimulators like BCG, levamisol and other stimulators, have been used for the treatment of eczema, atopic eczema, skin abscesses, and also auto-immune diseases (A. M. Tschernucha (Editor), Koscha, published by Medicina in 1982, Moscow).
For the treatment of flea-allergic dermatitis, the administration of antibody derived peptides has been successfully used (British patent application No 8913737). For the treatment of atopic eczema, desensitivisation has also been used with relatively good results (A. M. Tschernucha (Editor), Koscha, published by Medicina in 1982, Moscow).
In spite of the various different approaches in treating allergy, to our knowledge, no antigenic compounds preparable from keratinophilic fungi or yeasts have been used for the treatment of allergy.
In the context of the present invention the term “soluble” or “nonsoluble” refers to the solubility in aqueous solution. The term “antigenic preparation” refers to any composition of matter that is able to elicit an antigenic or immunogenic response. The term “modulating the immune response” refers to the ability of the antigenic preparations of the present invention to stimulate or enhance the immune response, for example as demonstrated by their ability to stimulate the proliferation of lymphocytes in cell culture, (a detailed review can be found in Strube et al. (1989) Vet. Med. Rev., 60, pp. 3–15, Büttner M. (1993) Comp. Immun. Microbiol. Infect. Dis., 16, No. 1, pp. 1–10).